1. Field of the Invention
The present invention relates to an ignition device which may be employed in 2-cycle engines for motorcycles or snowmobiles, especially to an ignition device having a contact point in which a magneto generator is used as an electric power source.
2. Description of Prior Art
In a conventional ignition device especially employed in a 2-cycle engine, a magneto generator is used as an electric power source, and a breaker contact and a primary winding of an ignition coil are connected in parallel to a generating coil of the magneto generator. In the ignition device of this kind, several high voltages other than that of a normal ignition timing are induced at a spark plug while the breaker contact opens. It comes from the fact that when the magnetic flux flowing through the generating coil changes from one direction to the other at a specific point, which is hereinafter referred to as a magnetically neutral point, change of the magnetic flux induces a sufficient high voltage to produce an ignition spark. These induced high voltages at the magnetically neutral points do not influence the engine operation during the normal running of the engine, since the high voltages are produced after the ignition spark at the normal ignition timing produced when the breaker contact opens, and further they are after a top deadcenter. However, when the engine rotates in the reverse direction by accident, the induced high voltages may be produced before and near the top deadcenter so that sufficient combustion energy is obtained to continue the reverse rotation of the engine.